An army of toxic cane toads is on the verge of overrunning Australia's world-famous Kakadu National Park, threatening to devastate its native species.

Large numbers of creatures are going to die and I think it's fanciful to believe everything will recover

Amphibian expert Mike Tyler

Wildlife experts say there is no chance of halting the invasion because the remote park's extensive rivers and swamps are too difficult to defend.

The toads are expected to reach the park within weeks.

Environment experts are working on plans to erect a 15km (10-mile) fence at Gurig National Park to try to block the toads' advance.

The species was introduced to Australia from South America in 1935 in a misguided attempt to wipe out cane beetles, a pest that was destroying sugar crops in north-east Australia.

The toads kill native wildlife such as snakes, lizards, crocodiles, turtles and water birds. When harassed they secrete poison carried in two sacs behind the head which can kill within minutes of being ingested.

Northern Territory Parks and Wildlife Commission acting director Mike Butler said the toads began migrating from neighbouring Queensland several years ago and are spreading across the remote province at about 100 kilometres (62 miles) a year.

Wildlife officers fear the toads will disturb hundreds of traditional Aboriginal communities in the Northern Territory, killing off their traditional food sources.